Method for the improved cleaning of edges of a wall

ABSTRACT

A method of using a cleaning robot for improved cleaning of edges of a wall having a projecting baseboard, includes using the robot to strike the baseboard in a first cleaning pass, causing an impact sensor to generate a first signal and a distance sensor to detect a first distance from the wall. The robot continues its first cleaning pass and strikes the baseboard a further time, causing the impact sensor to generate a second signal and the distance sensor to detect a second distance from the wall. A computer of the robot uses the signals to calculate two spatial points and a first straight line running through the points. The computer uses the distances and the two spatial points to establish an approach boundary of the cleaning robot relative to the wall. The computer controls the cleaning robot during subsequent cleaning passes exclusively using the one distance sensor.

The present invention relates to a method for the improved cleaning ofedges of a wall, which has a projecting skirting board, by means of acleaning robot. The invention further relates to a cleaning robot forcarrying out the method.

A cleaning robot with wheels and a drive facility and a suction facilityis disclosed in US 2017/0 332 853 A1, wherein the drive facility drivesthe wheels. Air which contains dust can be suctioned via the suctionfacility. Moreover, the cleaning robot has a sensor facility on an innerface of a front bumper bar, the sensor facility detecting when thecleaning robot strikes against an obstacle.

A self-propelled appliance with a LIDAR sensor is disclosed in US 2018/0149 753 A1, the size thereof being minimized by a transmitting moduleand receiving module being separated.

Generally nowadays, in addition to a mostly laser-based sensor systemfor distance measurement as a main data source for navigation andoptionally map creation, a large number of cleaning robots also have aresilient bumper bar with switching impact sensors, also called in shorta bumper. This serves to make objects detectable outside a detectionrange of a main distance sensor system for the cleaning robot, by thecleaning robot striking against the obstacles or objects and thetriggered impact sensor identifying the object as an obstacle. Theseobjects can be located outside the detection range, firstly due to thelimited lateral spatial resolution of the sensor system (object toosmall) and secondly due to falling below a measurement level (object toolow). The latter, in particular, relates to skirting boards along wallsif a distance sensor system is built into the front of the cleaningrobot or at the top of the cleaning robot.

In the last-mentioned cases, the cleaning robot often strikes againstthe skirting board, since a navigation software, which is based on thevalues delivered by the distance sensor system, assumes a distance fromthe wall which is greater by the thickness of the skirting board.

With such a cleaning robot, therefore, the cleaning of edges along suchskirting boards is not possible or only possible in an unsatisfactorymanner.

The present invention thus relates to the object of specifying a methodfor the improved cleaning of edges of a wall, which has a projectingskirting board, and in particular overcoming the drawbacks arising fromthe prior art.

This object is achieved according to the invention by the subject matterof the independent claim 1. Advantageous embodiments form the subjectmatter of the dependent claims.

The present invention is based on the general idea of detecting andconsidering a thickness of a skirting board along a wall and permittingthereby an improved cleaning of edges along a skirting board projectingfrom a wall, even though the cleaning robot is preferably exclusivelynavigated via a distance detector. The method according to the inventionfor the improved cleaning of edges of a wall, which has a projectingskirting board, is carried out by means of a cleaning robot, as follows:initially the cleaning robot is activated and, for example, in a firstcleaning pass strikes against the skirting board of the wall, whereuponan impact sensor of the cleaning robot generates a first signal and adistance detector arranged above the impact sensor detects a firstdistance from the wall. Then the cleaning robot travels back andcontinues its first cleaning pass until it strikes against the skirtingboard at least once more. Then the impact sensor generates a secondsignal while the distance detector at the same time detects a seconddistance from the wall. A computer facility of the cleaning robot thencalculates from the first and second signal two spatial points and afirst straight line which runs through these two spatial points. Byusing the previously determined distances and the two spatial points,the computer facility now determines an approach boundary of thecleaning robot in relation to the wall for subsequent cleaning passes.By the determined first straight line and the associated distances it isnow possible for the computer facility to control the cleaning robotduring subsequent cleaning passes exclusively via the distance detector,the cleaning robot only traveling as far as the approach boundary andthereby permitting an improved cleaning of edges. In this case, thedistances from the wall can be measured by the distance detector via adistance sensor or taken from a map in which the distances for differentspatial points have been previously stored. The method according to theinvention thus uses the coordinates of the points which have beendetermined during the cleaning of edges carried out for the first timein a room and which are namely the first and second spatial points inwhich a contact has occurred with the skirting board and at the sametime the distance detector has detected the distances from the wall, thevalues thereof showing that a greater distance from the wall is present.With the prior knowledge that the skirting boards are attached parallelto the wall, the thickness of the skirting board can be calculated fromthe two spatial points and the associated first and second distances, bya straight line through the two spatial points being determined, and thestandard distance of the determined straight line from the stored walldistance being calculated in the navigation software. If the cleaningrobot travels at the same time against a wall without a skirting board,the distance remaining from the wall is thus equal to zero, while in thecase of an impact against a skirting board projecting from the wall itdetects a distance of greater than zero. By the method according to theinvention, therefore, it is possible to enable the cleaning robot tolearn the approach boundaries, even in rooms with walls having skirtingboards, whereby it is possible to achieve an improved cleaning of anedge along the skirting board, and thus in particular an improvedcleaning result. It is also particularly advantageous that a navigationof the cleaning robot is possible virtually exclusively via the distancedetector, and at the same time the cleaning of edges can be improvedwithout additional sensor systems. This results in a significant benefitfor a user.

In an advantageous development of the method according to the invention,the cleaning robot continues its first cleaning pass until it strikesonce again against the skirting board, whereupon the impact sensorgenerates a further signal and the computer facility calculates anassociated further spatial point from the further signal. Alsoassociated with this further spatial point, when the cleaning robotstrikes against the skirting board the distance detector detects afurther distance from the wall which is associated with the furtherspatial point. The computer facility now considers the further spatialpoint, for adapting the first straight line calculated from the firstand second spatial points, only if this further spatial point fallsbelow a predefined distance from the first straight line. The computerfacility does not consider the further spatial point if the furtherspatial point is at or exceeds the predefined distance from the firststraight line. As a result, it is always possible to adapt thecalculated first straight line and thereby to relativize or compare ameasuring inaccuracy of individual measured spatial points. With thisadvantageous development of the method according to the invention, it isalso possible to differentiate between a random impact of the cleaningrobot against an obstacle and an impact against the skirting board, andas a result to leave out the random impact of the cleaning robot againstan obstacle relative to an adaptation of the first straight line. Thisis the case, in particular, if the further spatial point is at orexceeds the predefined distance from the first straight line. In thiscase, therefore, it can be concluded with relatively high reliabilitythat the further spatial point does not belong to the first straightline but is caused by a random impact against a different obstacle. As aresult, it is also possible to provide a self-learning effect which canbe perceived by a user, and at the same time it is possible to minimizeconcerns which are possibly present regarding damage to the skirtingboard by a repeated impact.

In a further advantageous embodiment of the method according to theinvention, the computer facility calculates a second straight line fromthe distances from the wall which have been detected at least at thefirst and second spatial points, and discards the first straight line ifa predefined angular deviation between the two straight lines isexceeded. Generally, the first straight line, which is located throughat least the first and second spatial points, would have to run parallelto the wall, i.e. theoretically the first and second distances wouldhave to be at least approximately the same, provided the thickness ofthe skirting board is identical. Thus in the ideal case the predefinedangular deviation would have to be equal to zero, so that the first andsecond straight lines run in parallel. If the lines do not run inparallel, by means of this advantageous embodiment of the methodaccording to the invention, a predefined angular deviation isestablished, for example of 0.2 to 0.5 degrees, which potentially can becaused by the presence of uneven wall plaster. Greater angulardeviations, however, would indicate that the first straight linecontains an error so that this first straight line is preferablydetermined once again.

In a further advantageous embodiment of the method according to theinvention, the first distance corresponds to a thickness of the skirtingboard at the first spatial point. Similarly, the second distance alsocorresponds to a thickness of the skirting board at the second spatialpoint. Generally, with skirting boards of equal thickness, the first andsecond distance would have to be of the same size. For example, acontrol of the method according to the invention is also possiblethereby, so that with each impact against the skirting board thecomputer facility determines the associated spatial point and theassociated distance from the wall, and compares the individual distanceswith one another, wherein only tolerance-induced deviations of thedistances, which for example indicate manufacturing tolerances of theskirting board, can be permitted here.

In this case, the distance detector can have a distance sensor formeasuring the distance from the wall at the respective spatial point,whereby a permanent detection of the spatial conditions and a continuousadaptation of the approach to the skirting board or the approachboundary are possible. Alternatively, it is also conceivable that, fordifferent spatial points, individually associated distances from thewall and thus thicknesses of the skirting boards, present at therespective spatial point, are input in advance into a map, for examplevia an app, and with an impact against the skirting board the distancesensor uses the distance input for this spatial point. With thepossibility of specifying the thickness/hardness of the skirting boardsin the app, it is possible to achieve an improvement in the navigationbehavior and the cleaning of corners and edges. This is possible, forexample, for each room separately. Thus it is possible to adapt thedistance of the cleaning robot from the skirting board accurately to theconditions. This could be increased further and individual walls or evenindividual wall portions could be changed, or the thicknesses of theskirting boards attached thereto could be input separately. Thus, forexample, a full-length mirror could be incorporated in the map and thecleaning robot would navigate differently in this region. The cleaningof corners and edges is thus improved without the use of a rotating sidebrush. Moreover, the constant impact against harder skirting boards, andthus also damage thereto, could be prevented thereby and thus thecleaning robot could have a smarter navigation.

The present invention is also based on the general idea of specifying acleaning robot having an impact sensor and a distance detector which isarranged thereabove in the operating state, and a computer facility,wherein the computer facility according to the invention is configuredfor carrying out the above-described method. As a result, it is possibleto provide a cleaning robot which is preferably exclusively navigatedvia a distance detector and at the same time achieves a significantlyimproved cleaning result, since it detects a spatial boundary present inwalls with skirting boards significantly more effectively than waspossible with the previous cleaning robots.

In a further advantageous embodiment of the cleaning robot according tothe invention, the distance detector or the at least one distancedetector is arranged at the top on the cleaning robot, for example in atower, or on the front side thereof above the impact sensor. As aresult, it is possible to arrange the distance detector sufficientlyhigh that it always detects a distance from the respective wall above askirting board and thereby the method according to the invention can becarried out.

Expediently, the impact sensor is arranged in a resilient bumper bar ofthe cleaning robot. As a result, a relatively light impact of thecleaning robot against the skirting board can be achieved, whereby inparticular damage of any kind can be virtually entirely eliminated.

Further important features and advantages of the invention emerge fromthe subclaims, from the drawings and from the associated description ofthe figures by way of the drawings.

It goes without saying that the aforementioned features to be describedin more detail below can be used not only in the respectively specifiedcombination but also in other combinations or individually withoutdeparting from the scope of the present invention.

Preferred embodiments of the invention are shown in the drawings and aredescribed in more detail in the following description, wherein the samereference characters refer to components which are the same or similaror functionally the same.

In the drawings, in each case schematically

FIG. 1 shows a cleaning robot according to the invention when carryingout a method according to the invention for improved cleaning of edgesof a wall,

FIG. 2 shows individual method steps of the method according to theinvention,

FIG. 3 shows a view as in FIG. 2 but with a different approach of thecleaning robot relative to the wall.

According to FIGS. 1 to 3 , a cleaning robot 1 according to theinvention has at least one impact sensor 2 and a distance detector 3which is arranged thereabove in the operating state, i.e. during normaltravel, and a computer facility 4. The cleaning robot 1 shown accordingto FIGS. 1 to 3 has in this case two distance detectors 3, namely adistance detector 3 arranged at the top in a tower and a distancedetector on the front side. According to FIGS. 1 to 3 , a wall 6defining a room 5 with a skirting board 7 arranged in front of said wallis additionally shown, wherein the cleaning robot 1 cleans a floor 8 ofthe room 5. In order to be able to carry out at the same time, inparticular, an improved cleaning of edges of the wall 6 with theskirting board 7 projecting therefrom, the method according to theinvention is provided as described in the following paragraphs:

In this method according to the invention, the cleaning robot 1 isinitially activated and strikes against the skirting board 7 with afirst cleaning pass, whereupon the impact sensor 2 generates a firstsignal and the distance detector 3 determines a first distance a fromthe wall 6. This is denoted according to FIGS. 2 and 3 by the methodstep A. Then the cleaning robot 1 continues its first cleaning passuntil it strikes against the skirting board 7 at least once more, whichis denoted according to FIGS. 2 and 3 by the method state C. When thecleaning robot strikes again against the skirting board 7 the impactsensor 2 generates a second signal and the distance detector 3 detects asecond distance a from the wall 6. The computer facility 4 of thecleaning robot 1 now calculates from the first and second signal twospatial points P₁ and P₂ (see FIGS. 2 and 3 ) and a first straight linerunning through these two spatial points P₁ and P₂. This first straightline runs according to FIG. 1 on an outer face of the skirting board 7.By using the distances a at the individual spatial points P₁ and P₂, andthe two spatial points P₁ and P₂, the computer facility 4 now determinesan approach boundary of the cleaning robot 1 relative to the wall 6 forthe subsequent cleaning passes. In this case, the distance a between thecleaning robot 1 and the wall 6 is corrected by the determined thicknessof the skirting board 7 so that in the subsequent cleaning passes thecleaning robot 1 travels in a significantly improved manner along theskirting board 7 and can carry out a significantly improved cleaning ofthe edges there.

By the method according to the invention, it is possible for the firsttime to navigate the cleaning robot 1 exclusively via a distancedetector 3, and this is the case even with walls 6 which have skirtingboards 7 arranged in front of said walls, wherein at the same time byconsidering the thickness of the skirting board 7, i.e. the distance a,a particularly accurate approach of the cleaning robot 1 to the approachboundary or skirting board 7 and thus a significantly improved cleaningof edges is made possible.

In this case, the distance detector 3 can have a distance sensor formeasuring the distance a from the wall 6 at the respective spatial pointP₁, P₂, or generally at any spatial point P, whereby a permanentdetection of the spatial conditions and a continuous adaptation of theapproach to the skirting board 7 or the approach boundary takes place.Alternatively, it is also conceivable that, for different spatial pointsP, individually associated distances a from the wall 6 and thusthickness of the skirting boards 7 present at the respective spatialpoint P are input in advance, for example via an app, and with an impactagainst the skirting board 7 the distance detector 3 uses the distanceinput for this spatial point P. With the possibility of specifying thethickness/hardness of the skirting boards 7 in the app, it is possibleto achieve an improvement in the navigation behavior and the cleaning ofcorners and edges. This is possible, for example, for each roomseparately. Thus it is possible to adapt the distance a of the cleaningrobot 1 from the skirting board 7 accurately to the conditions. Thiscould be increased further and individual walls 6 or even individualwall portions could be changed, or the thicknesses of the skirtingboards 7 attached thereto could be input separately. Thus, for example,a full-length mirror could be incorporated in the map and the cleaningrobot 1 would navigate differently in this region. The cleaning of thecorners and edges is enhanced to the best possible cleaning (without theuse of a rotating side brush). Moreover, the constant impact againstharder skirting boards, and thus also damage thereto, could be preventedthereby and thus the cleaning robot 1 could have a smarter navigation.

In a development of the method according to the invention, the cleaningrobot now continues its first cleaning pass until it strikes againagainst the skirting board 7, whereupon the impact sensor 2 generates afurther signal and the distance detector 3 detects a further distance afrom the wall. The computer facility 4 calculates from the furthersignal a further spatial point which is considered for adapting thefirst straight line calculated from the first and second spatial pointsP₁ and P₂, if the further spatial point falls below a predefineddistance from the first straight line, and is not considered if thisfurther spatial point is at or exceeds the predefined distance from thefirst straight line. As a result, it is possible in particular todifferentiate clearly between a random impact of the cleaning robot 1against an obstacle, from an impact against the skirting board 7 and toeliminate the random impact. Naturally, as a result, further measuredpoints can also be detected by a regression direction and included inthe calculation of the straight line, whereby this can be adapted orimproved.

The computer facility 4 can also calculate a second straight line fromthe distances a from the wall 6 detected at least at the first andsecond spatial points P₁ and P₂, and discard the first straight line ifa predefined angular deviation between the two straight lines isexceeded.

According to FIGS. 2 and 3 , the two straight lines G₁ and G₂ would haveto run in parallel and thereby have an angular deviation of 0 degrees.By the predetermination of the predefined angular deviation, for exampleof 0.5 degrees, in this case the first straight line G₁ can be discardedif the angular deviation is too great and this indicates a measuringinaccuracy when the first straight line G₁ is created.

Generally in the method according to the invention, the distance abetween the cleaning robot 1 and the wall 6, which is detected by thedistance detectors 3, for example, and which is measured or is read froma map with previously input values, corresponds to the thickness of theskirting board 7. The distances a from the respective spatial points P₁and P₂ would accordingly have to be generally identical.

By the method according to the invention and the cleaning robot 1according to the invention, it is possible for the first time to achievethereby a navigation which is controlled purely via a distance detector3, with at the same time an improved cleaning of edges in the case ofwalls 6 which have skirting boards 7. In particular, an additionalcomplex sensor system, such as for example a LIDAR system, is notrequired.

LIST OF REFERENCE CHARACTERS

-   -   1 Cleaning robot    -   2 Impact sensor    -   3 Distance detector    -   4 Computer facility    -   5 Room    -   6 Wall    -   7 Skirting board    -   8 Floor    -   a Distance    -   a₁ First distance    -   a₂ Second distance    -   G₁ First straight line    -   G₂ Second straight line    -   P Spatial point    -   P₁ Spatial point    -   P₂ Spatial point

1-9. (canceled)
 10. A method of using a cleaning robot for the improvedcleaning of edges of a wall having a projecting baseboard, the methodcomprising: providing the cleaning robot with at least one impact sensorand at least one distance detector disposed above the at least oneimpact sensor in an operating state; using the cleaning robot to strikeagainst the baseboard in a first cleaning pass, causing the at least oneimpact sensor to generate a first signal and causing the at least onedistance detector to detect a first distance from the wall; using thecleaning robot to continue the first cleaning pass until the cleaningrobot strikes against the baseboard at least once more, causing the atleast one impact sensor to generate a second signal and the at least onedistance detector to detect a second distance from the wall; using acomputer facility of the cleaning robot to calculate from the first andsecond signals two spatial points and a first straight line runningthrough the two spatial points; using the computer facility to determinean approach boundary of the cleaning robot relative to the wall forsubsequent cleaning passes, by using the distances and the two spatialpoints; and using the computer facility to control the cleaning robotduring subsequent cleaning passes exclusively by using the at least onedistance detector, causing the cleaning robot to only travel as far asthe approach boundary and thereby permitting an improved cleaning ofedges.
 11. The method according to claim 10, which further comprises:using the cleaning robot to continue the first cleaning pass until thecleaning robot strikes once again against the baseboard, causing the atleast one impact sensor to generate a further signal and the at leastone distance detector to detect a further distance from the wall; usingthe computer facility to calculate a further spatial point from thefurther signal; and using the computer facility to consider the furtherspatial point for adapting the first straight line calculated from thefirst and second spatial points upon the further spatial point fallingbelow a predefined distance from the first straight line, and using thecomputer facility to not consider the further spatial point upon thefurther spatial point being at or exceeding the predefined distance fromthe first straight line.
 12. The method according to claim 10, whichfurther comprises using the computer facility to calculate a secondstraight line from the distances from the wall detected at least at thefirst and the second spatial points and to discard the first straightline upon a predefined angular deviation between the two straight linesbeing exceeded.
 13. The method according to claim 10, which furthercomprises causing the first distance to correspond to a thickness of thebaseboard at the first spatial point.
 14. The method according to claim13, which further comprises causing the second distance to correspond toa thickness of the baseboard at the second spatial point.
 15. The methodaccording to claim 10, which further comprises: using a distance sensorof the at least one distance detector for measuring the distance fromthe wall at a respective spatial point, or for different spatial points,inputting individually associated distances from the wall and thusthicknesses of the baseboards in advance and, upon an impact against thebaseboard, causing the at least one distance detector to use thedistance input for the spatial point.
 16. A cleaning robot, comprising:at least one impact sensor; at least one distance detector disposedabove said at least one impact sensor in an operating state; and acomputer facility configured for carrying out the method according toclaim
 10. 17. The cleaning robot according to claim 16, which furthercomprises a top and a front side of the cleaning robot, said at leastone distance detector being disposed at said top or on said front sideabove said at least one impact sensor.
 18. The cleaning robot accordingto claim 16, which further comprises a resilient bumper bar in whichsaid at least one impact sensor is disposed.